Coating material supply device

Abstract

A coating material supply device in which coating material is pumped out at a predetermined flow rate and supplied at a constant flow rate to a coating machine. The device includes a plurality of double-acting reciprocal pumps, each having an inlet for the coating material supplied from a coating material supply source and an exit for discharging the coating material by the pressure of hydraulic fluid supplied at a constant flow rate from a hydraulic fluid supply source. The exits are connected to coating material selection valves connected in parallel with each other to the coating machine, and connected to switching valves that selectively switch the flow channel for the hydraulic fluid supplied from the hydraulic fluid supply source in response to the switching operation of the coating material selection valves. A flow rate control mechanism for maintaining the flow rate of the hydraulic fluid constant is disposed in the flow channel for the hydraulic fluid, between the hydraulic fluid supply source and the switching valves.

What is claimed is: 
     
       1. A coating material supply device in which coating material is pumped out at a predetermined flow rate and supplied at a constant flow rate to a coating machine, wherein said device comprises: a plurality of double-acting reciprocal pumping means, each having an inlet for the coating material supplied from a coating material supply source and an exit for discharging said coating material by the pressure of hydraulic fluid supplied at a constant flow rate from a hydraulic fluid supply source, connected to coating material selection valves connected in parallel with each other to the coating machine, and connected to switching valves that selectively switch flow channel for the hydraulic fluid supplied from the hydraulic fluid supply source in response to switching operation of said coating material selection valves,   a flow rate control mechanism for maintaining the flow rate of the hydraulic fluid constant being disposed to the flow channel for said hydraulic fluid between the hydraulic fluid supply source and said switching valves,   there being a connection between a hydraulic pressure source and the pumping means,   the pumping means having a member responsive to hydraulic pressure, said member being connected to the pumping means,   said coating material selection valves being provided in controlling relationship to said material supply source and exits, and   said switching valves being provided in individual connections between the hydraulic fluid supply source and the pumping means.   
     
     
       2. A coating material supply device as defined in claim 1, wherein the coating material comprises paints of different colors and a paint of a specific color is selected from them by said coating material selection valve that functions as a color-change valve. 
     
     
       3. A coating material supply device as defined in claim 1, wherein the flow rate control mechanism is adapted to conduct feedback control for the number of rotation of the rotary pump that supplies the hydraulic fluid based on the flow rate of the hydraulic fluid detected by a flow meter. 
     
     
       4. A coating material supply device as defined inn claim 1, wherein the flow rate control mechanism is a gear pump the rotation of which is controlled based on the predetermined number of rotation depending on the flow rate of the hydraulic fluid.